WO2021064048A1

WO2021064048A1 - Planar glass element and method for separating a glass substrate into a plurality of such glass elements

Info

Publication number: WO2021064048A1
Application number: PCT/EP2020/077413
Authority: WO
Inventors: Joachim Ebmeier; Jeremy Rendell
Original assignee: Flabeg Deutschland Gmbh
Priority date: 2019-10-02
Filing date: 2020-09-30
Publication date: 2021-04-08
Also published as: US20220340472A1; JP2022551075A; DE102019215264A1; CN114630723A

Abstract

The invention relates to a planar glass element (12) having two opposite side faces (22) which are connected to one another laterally by a number of contact faces (20). Adjacent filament-like impairments (24) forming elongate indentations are provided in the or each edge face (20), and the/each edge face (20) is arranged at an incline to the side faces (22). Said planar glass element is particularly well suited for use in a large number of possible applications. In accordance with the invention each edge face (20), in its region provided with the filament-like impairments (24), has a surface roughness with a mean roughness value of at least 0.3 µm, and preferably of at most 2 µm, particularly advantageously of approximately 1 µm.

Description

description

Disc-shaped glass element and method for separating a glass substrate into a plurality of such glass elements

The invention relates to a disk-shaped glass element with two opposing side surfaces which are laterally connected to one another via a number of edge surfaces, wherein in the or each edge surface adjacent, elongated depressions forming filamentary damage are provided, and wherein the or each edge surface obliquely the side faces. It also relates to a method for separating a glass substrate into a plurality of such glass elements, in which a perforation formed by a sequence of filamentary damage is generated in the glass substrate by means of a perforation laser along an intended cutting line and this is then broken along the perforation, the perforation laser for the incidence of the laser beams on the glass substrate, which is inclined relative to the surface normal of the glass substrate, is set.

A large number of processes and concepts can be used to cut or separate glasses or glass elements. Among other things, laser-based processes such as laser filament cutting can be used, especially with regard to complex cut shapes or high precision requirements.

In laser filament cutting, also known as filamentation, non-linear optical effects are used. A suitably selected laser - hereinafter also referred to as a "perforation laser" - is used, the focus of which is placed under the glass surface of the glass element to be cut into the material. Because of the so-called self-focusing, there is local heating in the glass material at the point where the focal point lies, the formation of local stresses and a change in the refractive index. This makes it seem small at first

(WTERGAU-SQL01 \ WINPAT2 \ DOCUMENT \ AMT \ 198110O docx) last saved: 30 September 2020 Volume element like a lens, and further such filaments can be created in its continuation. If the laser beam is guided over the glass, a so-called filament curtain is created, which acts like a perforation and can serve as a starting point for a subsequent separation step, for example by breaking. This concept of laser filamenting is known, for example, from US 2013/0126573 A1.

From DE 102015 111 491 A1 a disk-shaped glass element of the type mentioned is known in which the lateral separating edge generated by the perforation formed by the filamentary damage during the subsequent separation or breaking process is inclined, i.e. inclined relative to the surface normal is. This is achieved in that the perforation laser used to generate the perforation in the glass substrate is set with its laser beam at an angle or inclined to the surface of the glass substrate. According to the teaching of DE 102015 111 491 A1, the resulting inclined or inclined separating or edge surface of the glass element is particularly intended to facilitate the detachment of inner contours when separating the glass elements, even with complex contours or cutting lines.

The invention is now based on the object of developing a glass element of the type mentioned above for particularly good usability in a variety of possible uses. Furthermore, a method of the type mentioned above that is particularly suitable for the production of the glass element is to be specified.

With regard to the glass element, this object is achieved according to the invention in that the respective, beveled edge surface in its area provided with the filamentary damage has a surface roughness with a mean roughness of at least 0.3 μm, and preferably of at most 2 μm, in a particularly advantageous embodiment of about 1 pm.

The invention is based on the idea that the beveled edge or edge guide provided in the known Glasele element actually for reasons of easier separation or product separation in the sense of an improvement of the product properties for its later use as a basis for an advantageous

(WTERGAU-SQL01 \ WINPAT2 \ DOCUMENT \ AMT \ 198110O docx) last saved: 30 September 2020 Further development of the glass element could be used. In particular, it can be taken into account that such a beveled side edge is visually conspicuous and can therefore be optically recognized more easily than conventional, “straight” edges both in manual and machine processing. As an alternative or in addition, such a beveled side edge can be upgraded in particular for suitability for subsequent gluing. In order to improve the glass element specifically with regard to these two functionalities, i.e. easier visual recognition and / or improved suitability for gluing, the roughness or roughness of the surface in the area of the edge surface or edge surfaces is now provided as a suitable parameter for this.

It is particularly taken into account that the roughness on the one hand is an indication of the optical perceptibility. Furthermore, the degree of gloss is a criterion, but also the scattered light (diffusion) through the typical fracture surface with many small individual surfaces, since glass breaks brittle. In particular, it must be taken into account that normal broken or processed glass edges are often difficult to recognize. The contrast is usually low because it is a transparent material, the surfaces of which can often also be reflective. In particular, with laser modification cutting, the standard process creates high-quality surfaces that are relatively inconspicuous in the direction of the surface normal. This can now be taken into account in the finished glass element in particular by the fact that, in comparison with the immediately adjacent surface areas of the side surfaces of the glass element, which usually have an extremely low surface roughness, the roughness provided now enables a targeted contrast to be produced through which the Recognizability can be significantly improved. On the other hand, the intended surface roughness is particularly favorable for the bondability, since in this way an intimate material contact with an adhesive can be established in a particularly simple manner.

The delimitation of the "area provided with the filamentary damage" from the other areas of the edge surface is preferably based on the criterion that the individual filaments are usually set at a constant target distance from one another, so that the "area provided with the filamentary damage" where the next adjacent filament ends in one

(WTERGAU-SQL01 \ WINPAT2 \ DOCUMENT \ AMT \ 198110O docx) last saved: 30 September 2020 Distance of more than twice this nominal distance to the respective filament is set.

Advantageous refinements of the invention are the subject matter of the subclaims.

In particular with regard to the other parameters usually selected for such a glass element, such as the glass thickness or the lateral extent, the respective, beveled edge surface in its area provided with the filament-like damage very particularly preferably has a surface roughness with a mean roughness of about 1 μm .

In a particularly advantageous development, further geometry parameters of the glass element are also specifically selected to be suitable for supporting the functionalities to be improved. Turning away from the design criteria in the known glass element with the intended design goal of facilitated separation of the elements from each other, the edge surface is now particularly preferably inclined by an inclination angle of 0.5 ° to 3 ° relative to the surface normal of the sides. Thus, comparatively small angles of inclination of the edge surface relative to the surface normal of the side surfaces are particularly preferred. In particular, when selecting the parameters for the angle of inclination, a combination of design criteria is taken into account in a particularly preferred embodiment: on the one hand, there is a general endeavor to avoid generally deviating angles, since 90 ° angles are often specified on the component side. In this sense, comparatively small angles should be aimed for. On the other hand, however, an increase in the angle means that it is increasingly easier to recognize; A doubling of the processed area in the top view generally means twice as good visibility. From this point of view, larger angles of inclination would be preferable, preferably in compliance with the boundary conditions given on the component side.

As has also surprisingly been found, the effects and functionalities that can be achieved through the targeted setting of the surface roughness are particularly useful for glass elements of comparatively small thickness. The glass element therefore particularly preferably has a thickness of at most 6 mm, preferably at most 3 mm.

(WTERGAU-SQL01 \ WINPAT2 \ DOCUMENT \ AMT \ 198110O docx) last saved: 30 September 2020 With regard to the method, the stated object is achieved in that the filaments forming the perforation are produced in the glass substrate in such a way that the edge surface that occurs after breaking and has the damage caused by the filaments has a surface roughness with a mean roughness of at least 0.3 μm, and preferably of at most 2 gm, in a particularly advantageous embodiment of about 1 gm.

In particular, the knowledge that the optical quality of the edge is decisive for the recognizability is taken into account. In addition to the material properties such as optical density, interface size in the case of fracture, brittleness and the like, it is determined by the processing (polished, ground, broken, ..). In laser modification cutting, the surface of the edges consists of at least two surface areas, namely the filament itself and the break area between the filaments. The edge surface and in particular its surface roughness can be influenced by the number, dimensioning, position and also the design of the filaments. A large number of small-dimensioned filaments at a short distance lead to a surface with a comparatively low roughness. Large filaments, on the other hand, increase the surface roughness. The half-channel that is created in the event of a break in the middle of the modification is part of the surface and thus also contributes to the surface roughness. The area of fracture between the modifications determines the rest of the surface properties. When setting the surface roughness, the ratio of free fracture surface to filament fracture surface must also be taken into account. It is furthermore also conceivable to introduce deliberately pronounced (e.g. particularly large or small, ..) modifications at fixed intervals in addition to the normal ones in order to achieve the desired surface roughness.

Advantageously, during the production of the perforation or the filaments forming it, the perforation laser is set at an incline to the surface normal of the glass substrate so that the filamentary damage that forms in the glass substrate is inclined in its longitudinal direction relative to the surface normal of the glass substrate by an angle of inclination of between 0.5 ° and are inclined by 3 °. It must be taken into account that - given by the laws of refraction - the filament

(WTERGAU-SQL01 \ WINPAT2 \ DOCUMENT \ AMT \ 198110O docx) last saved: 30 September 2020 The sensor direction in the glass substrate does not necessarily correspond to the laser propagation direction, i.e. the direction of the laser beams incident on the substrate.

Regardless of the explained achievable improvement in the functional properties of the glass element through the intended setting of the surface roughness in the area of the edge surfaces, the inclined design of the edge surfaces also offers the already known advantages when removing or separating the glass elements when separating the glass substrate. When the components are separated or separated from adjacent components or surrounding material, the inclined cut has a positive effect, especially in a removal direction parallel to the surface normal, since this results in a removal bevel. The components are generally interlocked with one another due to the surface roughness. The removal slope, i.e. the opening, divergent orientation in the removal direction, reduces the risk of damage during removal through mussels or broken edges. Automation of the removal is thus facilitated or even made possible in the first place by the removal slope. In order to promote this even further, additional measures to facilitate the separation or separation of the glass elements from one another are provided in an alternative or additional advantageous development, which is also regarded as being independently inventive. For this purpose, after the filamentary damage has been introduced, the glass substrate is advantageously locally heated or locally cooled in an area in the vicinity of the perforation. This creates targeted thermal or mechanical stresses in the vicinity of the perforations in the glass substrate, which enlarge the separating gap and thus reduce the “toothing” during removal.

The advantages achieved with the invention consist in particular in the fact that the glass element can be upgraded and improved in terms of its functionalities for a multitude of subsequent uses through the targeted adjustment of the surface roughness of the edge surface. In addition to the simplification of the removal or separation of the components that can be achieved by the beveled edge surfaces, as provided in the present case but also by comparatively small inclination angles, an easier further processing is also automated, due to the improved visual recognizability, and / or a improved bondability achievable.

(WTERGAU-SQL01 \ WINPAT2 \ DOCUMENT \ AMT \ 198110O docx) last saved: 30 September 2020 In particular, the users of the glass element, e.g. B. when installing in more complex systems or when processing to the end product, the process-related damage caused by the laser filamentation for aesthetic or process-related reasons, for example because of scattered light caused by edge damage such as mussels when coupling light z. B. for displays. Such disruptive effects can be kept low, especially due to the improved removal of components, even with cuts at an angle only slightly deviating from 90 °. However, precisely for the comparatively small component thicknesses that are particularly preferred, these deviations are not seen as particularly disruptive or are accepted. Through the targeted use of the edge surface properties provided in the present case, recognizability can thus be improved without having to accept the disadvantages mentioned.

An embodiment of the invention is explained in more detail with reference to a drawing. Show in it:

FIG. 1 schematically a cutting system for cutting glass elements,

FIG. 2 schematically shows a section of a glass substrate with incorporated filaments, and

FIG. 3 a glass element.

The same parts are provided with the same reference symbols in all figures.

The cutting system 1 according to FIG. 1 is provided for cutting glass substrates 2 by laser filament cutting. For this purpose, the cutting system 1 comprises a perforation laser 4 designed for filamentation, which can be controlled via an associated control device 6. Via the activation by means of the control device 6, the focal point of the perforation laser 4 can be guided along a predeterminable cutting line 8 on the surface of the glass substrate 2 to be cut. As a result of the design of the perforation laser 4, there is local heating in the glass material at the point at which the focal point lies, the formation of local stresses

(WTERGAU-SQL01 \ WINPAT2 \ DOCUMENT \ AMT \ 198110O docx) last saved: 30 September 2020 and to a change in the refractive index, so that ultimately as a result of non-linear optical effects in the glass material along the cutting line 8 so-called filaments are formed, which form the desired perforation 10.

For the actual cutting of the glass substrate 2, that is to say for its separation into individual glass elements 12, d. H. for separating the parts along the cutting line 8 and the perforation 10, a breaking process is then provided for filamentation, ie after the perforation 10 has been introduced. To facilitate or support the separation or separation of the glass elements 12 from one another, the introduction of thermal or mechanical stresses in the vicinity of the perforation 10 of the glass substrate 2 is provided. For this purpose, in the exemplary embodiment, after the filaments forming the perforation 10 have been introduced, the glass substrate 2 is locally heated in an area in the vicinity of the perforation 10; alternatively, however, local cooling could also be seen. In the exemplary embodiment, a locally positionable relative to the surface of the glass substrate 2 fusing device 14 is vorgese hen for the purpose of local heating.

The cutting system 1 is designed for easier removal or separation of the glass elements 12 produced during the separation. In particular, the recognition is taken into account that, in principle, a gap-free separation is generated during perforation or modification laser cutting. If the glass elements 12 are then to be detached from one another or from the surrounding bulk material, this is often not possible without damage. In addition, the separation and removal is made more difficult with increasingly complex cuts such as radii, corners or polygons. Typical damage caused by removal is mussels, splits or cracks on the separating edges. In order to counteract this and to facilitate the removal or separation of the glass elements 12, the perforation laser 4 is set when the filaments forming the perforation 10 are introduced so that the laser beams strike the glass substrate 2 at an angle relative to the surface normal of the glass substrate indicated by the arrow 16.

This inclined or inclined impingement of the laser beams leads to the filamentary damage occurring in the glass substrate 2 also running inclined or inclined to the surface normal of the glass substrate 2. This is shown schematically in FIG. 2

(WTERGAU-SQL01 \ WINPAT2 \ DOCUMENT \ AMT \ 198110O docx) last saved: 30 September 2020 shows. As can be seen there, the laser pulses 18 arriving in the glass substrate 2 at an angle α relative to the surface normal of the glass substrate 2 are broken. Due to the refraction of light, the light propagates within the glass substrate 2 at a refractive index n of the material of the glass substrate 2 at an angle β relative to the surface normal, which can be derived from the angle of incidence of the laser pulses 18 according to the relationship sinß = (1 / n) sin a is. Accordingly, inclined laser pulses 18 in the glass substrate 2 also result in obliquely running modifications or filamentary damage.

When the glass substrate 2 is subsequently broken or separated, glass elements 12 with sloping or inclined edge surfaces 20 arise accordingly. As the enlarged section in FIG. 3, the result of the separation process is therefore a disk-shaped glass element 12 with two opposing side surfaces 22 which are laterally connected to one another via a number of edge surfaces 20. The edge surface 20 is tilted by the angle of inclination β or aligned inclined to the surface normal of the side surface 22, d. H. it runs obliquely to the side surfaces 22. Due to the process and manufacturing process, filamentary damage 24 running next to one another, elongate depressions forming depressions, is present in the edge surface 20 as relics of the perforation 10 previously made in the glass substrate 2.

The glass element 12 is designed, in addition to the facilitating removal and separation achieved via the inclined orientation of the edge surface 20, for particularly good usability in a large number of possible applications. This is based on the knowledge that the inclined edge surface 20 can be designed in a targeted manner in the sense of providing additional functionalities, in the present case in particular visual recognizability and / or adhesiveness. In order to achieve this, the edge surface 20 has a surface roughness with a mean roughness value of approximately 1 μm in its area provided with the filamentary damage 24.

The intended surface roughness is set during the filamentation step through a suitable selection of parameters and process control. In particular, the number, the dimensions, the position and also the design of the filaments are

(WTERGAU-SQL01 \ WINPAT2 \ DOCUMENT \ AMT \ 198110O docx) last saved: 30 September 2020 essential parameters for the resulting surface roughness, and they are suitably selected and adjusted according to the desired surface roughness. It is furthermore also conceivable to introduce deliberately pronounced (e.g. particularly large or small, ..) modifications at fixed intervals in addition to the normal ones in order to achieve the desired surface roughness.

The illustration in FIG. 3 is to be understood as a schematic sketch in the sense of improved comprehensibility, in particular with regard to the angle of inclination of the edge surface 20, and not to scale. With regard to its dimensions and geometry parameters, the glass element 12 in the exemplary embodiment is rather designed with a comparatively small angle of inclination β of the edge surface 20 relative to the surface normal of the side surfaces 22 of about 2 °. A large number of design criteria are thus taken into account in a particularly favorable manner. In particular, such a choice of the angle of inclination ß on the one hand a sufficient, the removal or separation facilitating removal slope can be formed, on the other hand, interference effects such as scattered light by edge damage such as mussels when coupling light z. B. can be kept particularly low for displays. Due to the envisaged surface roughness of the edge surface, it is nevertheless and precisely also for the envisaged comparatively small angles of inclination β that a clearly improved visual perceptibility and also an improved adhesiveness can be provided.

(WTERGAU-SQL01 \ WINPAT2 \ DOCUMENT \ AMT \ 198110O docx) last saved: 30 September 2020 List of reference symbols

1 cutting system

2 glass element

4 perforation lasers

6 control device

8 Cutting line 0 perforation

12 glass element

14 heater

16 arrow

18 laser pulse 0 edge surface 2 side surface 4 damage

(WTERGAU-SQL01 \ WINPAT2 \ DOCUMENT \ AMT \ 198110O docx) last saved: 30 September 2020

Claims

Expectations

1. Disc-shaped glass element (12) with two opposing side surfaces (22) which are laterally connected to one another via a number of edge surfaces (20), with filamentary damage in the or each edge surface (20) running next to one another, elongated depressions ( 24) are provided, and wherein the or each edge surface (20) is inclined to the side surfaces (22), characterized in that the respective edge surface (20) in its area provided with the filamentary damage (24) has a surface roughness with a mean roughness of has at least 0.3 pm.

2. Glass element (12) according to claim 1, the respective edge surface (20) of which in its area provided with the filamentary damage (24) has a surface roughness with a mean roughness of at most 2 μm, advantageously of approximately

1 pm.

3. Glass element according to claim 1 or 2, in which the edge surface (20) is inclined by an inclination angle of 0.5 ° to 3 ° with respect to the surface normal of the side surfaces (22).

4. Glass element (12) according to one of claims 1 to 3, which has a thickness of at most 6 mm, preferably at most 3 mm.

5. A method for separating a glass substrate (2) into a plurality of Glasele elements (12) according to one of claims 1 to 4, in which by means of a Perforati onslasers (4) along an intended cutting line (8) a sequence of filamentary damage (24) formed perforation (10) generated in the glass substrate (2) and this is then broken along the perforation (10), the perforation laser (4) for a relative to the surface normal of the glass substrate (2) inclined impingement of the laser beams on the glass substrate (2) is set,

(WTERGAU-SQL01 \ WINPAT2 \ DOCUMENT \ AMT \ 198110O docx) last saved: 30 September 2020 characterized in that the filaments forming the perforation (8) are produced in the glass substrate (2) in such a way that the edge surface (20) that arises after breaking and the damage (24) caused by the filaments has a surface roughness with a mean roughness of at least 0.3 gm, and preferably of at most 2 gm, in a particularly advantageous embodiment of about 1 gm.

6. The method according to claim 5, in which the perforation laser (4) is set inclined to the surface normal of the glass substrate (2) in such a way that the filamentary damage (24) forming in the glass substrate (2) with its longitudinal direction relative to the surface normal of the glass substrate ( 2) are inclined by an angle of inclination (ß) of between 0.5 ° and 3 °.

7. The method according to claim 5 or 6, wherein the glass substrate (2) after bringing the filamentary damage (24) is locally heated or locally cooled in an area in the vicinity of the perforation (8).